Various luggage items, such as briefcases, tote bags, duffle bags, and garment bags, are often provided with shoulder straps that can be completely detached. Similarly, the lower ends of the shoulder straps of backpacks often can be detached from the lower sides of the backpack body and stowed in a storage pocket. Detachable straps afford the user the option of carrying the luggage item by hand and permit the item to be transported as checked luggage on buses, trains, watercraft and aircraft with the straps stowed, thereby reducing the risk of damage due to the shoulder strap getting caught on conveyor equipment or other articles or objects during handling.
The predominant way of providing for detachment of shoulder straps of luggage items is by D-rings that are affixed to the body of the luggage item and capture hooks that are affixed to the straps. The D-rings are usually made of bent steel wire and the hooks of a cast metal, such as ZAMAC. The hardness of the cast metal hooks is significantly less than that of the steel D-rings, and the difference in hardness results in a high rate of wear of the portion of the hook that engages the D-ring. Over time, the wear produces a notch in the hook, which is a zone of stress concentration and weakness. It is not uncommon for the hook to break at the notch.